1. Field of the Invention
This invention is related to a feeder and a printer.
2. Description of the Related Art
Feeders for transporting a print medium along a U-shaped transporting path from a tray are disclosed in the art. This type of feeder is often used in, for example, a printer. The feeder used in a printer comprises a tray comprising a support surface upon which a print medium is to be placed, a feeding roller located at a position facing the support surface of the tray, the feeding roller feeding the print medium toward the U-shaped transporting path, a transportation guide forming the U-shaped transporting path, and a transporting roller located at a position adjacent to a downstream end of the U-shaped transporting path. The transporting roller and the feeding roller have a positional relationship that allows the transporting roller and the feeding roller to simultaneously make contact with the print medium. The feeder feeds the print medium into the transporting path by means of the feeding roller, and transports the print medium by means of the transporting roller to a printing device such as an ink jet head or the like that is disposed downstream.
The feeder further comprises a controller that controls the transporting roller and the feeding roller. The controller, for example, controls the transporting roller and the feeding roller such that the peripheral velocity of the transporting roller is greater than the peripheral velocity of the feeding roller. Alternatively, the controller controls the transporting roller and the feeding roller such that the driving of the feeding roller is halted when the print medium has reached the transporting roller. Alternatively, the controller controls the transporting roller and the feeding roller such that the feeding roller rotates in reverse when the print medium has reached the transporting roller. When the controller controls the transporting roller and the feeding roller in the manners described above, a tension is generated in the print medium moving through the transporting path, and bending of the print medium can thus be prevented.
However, when a tension is generated in the print medium, the pushing force exerted onto the print medium by the feeding roller becomes the transporting load for the transporting roller while the feeding roller and the transporting roller are simultaneously making contact with this print medium. It becomes difficult to transport the print medium stably when this transporting load is large.
A technique for reducing the transporting load is taught in, for example, Japanese Utility Model Publication 6-47243. A feeder taught in Japanese Utility Model Publication 6-47243 comprises a separating roller facing a feeding roller. A print medium is transported while being held between the feeding roller and the separating roller. The separating roller reduces the transporting load by separating from the feeding roller at a predetermined time.